Both p and n type semiconducting materials are commonly used to form semiconducting devices. A p-n junction diode is a typical example of a device containing such a junction between a p and n type material. The diode can be constructed by forming an interface or junction between a semiconducting material having holes as the majority carrier (the “p” material) and a semiconducting material having electrons as the majority carrier (the “n” material). In addition to single junction devices, multiple junctions can be formed consecutively to form other devices, such as p-n-p or n-p-n transistors. Known semiconducting materials suitable for use in forming p-n junctions include silicon, germanium, gallium arsenide, and boron carbide.
Conventionally, p-n junction devices can be formed as either heterojunction devices or homojunction devices. In heterojunction devices, two different semiconductor materials are selected to form a p-n junction. Based on the selection of materials, devices with various bias voltages can be created. Strain can be created at interfaces of dissimilar material, which can lead to structural defect failure. Different materials also have diffusion across the interface or side reactions leading to an al together different semiconductor, which can lead to eventual failure increased recombination for electron hole pairs.
In homojunction devices, the same bulk semiconductor material is used to form both halves of the p-n junction, but one or more dopants are added to one or both sides of the junction in order to modify the majority carrier. Homojunction devices typically have little or no strain at the junction interface. Due to fabrication difficulties and interdiffusion effects, however, it is difficult to create a sharp transition between the p and n materials. Devices with non-abrupt transitions between the p and n materials typically suffer from increased recombination at the p-n junction. Additionally, doping of the semiconductor materials can lead to introduction of other impurities, and some impurities may be activated by the incident radiation, particularly neutrons.
Heterojunction and homojunction devices, such as diodes, are useful for a myriad of applications. Heteroisomeric devices in accordance with the present invention are a new type of device that may find application in any of the myriad of uses where heterojunction and homojunction devices are employed, as well as new uses for which heterojunction and homojunction devices are ill-suited. One area of particular interest for heteroisomeric diodes is the conversion of the kinetic energy of particles incident upon them to signal pulses, thereby allowing electrical pulses to indicate particles incident upon the devices
What is needed are p-n junction devices that are effective for detection of incident particles. The devices should be capable of withstanding a variety of operating environments. The devices should be constructed of materials with a high neutron capture cross-section, and significant capture cross-section for other incident particles of interest, as well as stability against radiation damage.